Guest Post by Steven Goddard
The Guardian image below taken this week near Iceland has the caption “Smoke and ash billows from a volcano in Eyjafjallajokull, Iceland Photograph: Ingolfur Juliusson/Reuters”
The Guardian caption is for the most part incorrect. Note that the volcanic cloud is largely indistinguishable from the other clouds, except for it’s shape. The reason for the similarity is that the vast majority of the volcanic plume is water vapour, not ash and definitely not smoke. Where would smoke come from??? There aren’t any trees on Iceland to burn.
The abundance of gases varies considerably from volcano to volcano. However, water vapor is consistently the most common volcanic gas, normally comprising more than 60% of total emissions. Carbon dioxide typically accounts for 10 to 40% of emissions.
70% of the earth’s surface is covered with water. Where did that water come from? It is generally believed that most of it outgased from the interior of the earth during the first 700 million years of the earth’s existence.
Steam from the interiorToday most authors believe that early steam from the hot mantle but already cool atmosphere, caused the oceans in the very early stages of the planet. They reason from studies of chondrites (space rocks) in space that under compression, enough water could be released to form an ocean. Today one can observe the gases escaping from active volcanoes, and these too contain water. In this scenario, the oceans would still be increasing in size, a gradual process that would never really end.The amount of water stored in rocks of the primary lithosphere is estimated at 25E21kg (Hutchinson G E, 1957), whereas the water in all oceans is 1.35E21kg, so it is quite possible that all this water emerged slowly after rocks were compressed and heated while the atmosphere had cooled already.
We know that the oceans could not have condensed out of the early atmosphere, because even a 100% water vapour atmosphere would only contain 10 metres of liquid water. People have hypothesized that the oceans came from comets, but the hydrogen isotope ratios in the oceans are different than that seen in comets Halley, Hyakutake and Hale-Bopp.
The only plausible origin of the oceans is from the interior of the earth. So why don’t we see oceans on other planets and the moon? Liquid water only exists in a narrow range of temperatures and pressures. Other planets are too hot, too cold or too small to hold liquid water, though some of the moons of the giant planets may have liquid water.
Why is the relationship between volcanoes and water important? Because steam pressure is the primary driver of explosive volcanic eruptions.
Below are some images of potentially explosive eruptions :
Mt. St. Helens 1980 : Mostly steam, some ash, almost no smoke.
The video above shows the moment of the big eruption May 18, 1980
Mayon 1984 USGS photo : Steam rising, ash cloud falling down the sides of the mountain.
Fourpeaked Volcano, Alaska 2006 USGS photo : 100% steam
Tungurahua 2006 NASA EO image : Steam, ash and lava
Eyjafjallajökull 2010 NASA EO image : Steam, lava, ice
Below are USGS images of non-explosive eruptions at Mauna Loa, Hawaii
Note in the image above that there is some smoke on the left side – from burning trees, and a little steam at the summit. So what is the difference between explosive and non-explosive eruptions? The difference is mainly due to the presence or absence of water. Water mainly enters volcanoes from two primary sources.
- Subduction on the sea floor, and transport upwards into a magma chamber. (Mt. St. Helens)
- Melt from snow and ice above. (Eyjafjallajökull and Mt. St. Helens)
Mauna Loa on the other hand has very little water mixed in with the magma, as it is neither near a subduction zone nor is it covered with snow most of the time. So eruptions from Mauna Loa tend to produce lava rather than steam and ash.
Looking at the mechanics, it becomes clear that explosive volcanic eruptions can not occur in the absence of large amounts of steam. Liquids (like magma) have very low compressibility and can not store enough mechanical energy to cause an explosion. Gases on the other hand are extremely compressible and can store vast amounts of energy. Steam has the unique property that it is liquid until it comes in contact with the magma (or the overburden pressure becomes low enough to allow it to switch to vapour phase) – then it converts thermal energy into mechanical energy very efficiently. The world used to run off steam engines based on this principle.
Most modern power plants still use steam to convert thermal energy into mechanical energy. Same principle that makes volcanoes explode.
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@Walter M. Clark (20:33:36)
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GE 1:1 In the beginning God created the heavens and the earth. 2 And the earth was formless and void, and darkness was over the surface of the deep; and the Spirit of God was moving over the surface of the waters. (NASB) He created light and separated the light from the darkness. This was all on the first day of creation
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“separated the light from the darkness”
Waste of time imho, why not remove the darkness _before_ creating light ??
…and why work in the dark ? – I would create light as the very first thing
Most of the volcanic ‘smoke’ is actually volcanic ash (essentially very fine rock), which appears to actually be raining down from the downwind part of the cloud in the top picture of Eyjafjallajokull. But then normal smoke is also composed of particulates and often steam if burning wet wood. “Volcanic smoke” is a commonly used term, even if it does not refer to combustion.
Hawaiian volcanoes are basaltic, and thus much lower viscosity than the andesitic volcanoes on continental margins. But there are occasional explosive eruption on Hawaii when groundwater mixes with the magma.
Oeuf en visage, je peur. Steam is invisible, as is water vapour. What you see in clouds and the volcano plume is water droplets and/or ice crystals. Common parlance is wrong when referring to what is visible at the end of the jet of invisible steam issuing from a kettle as ‘steam’.
Tom T (20:35:02) : “I keep hearing that one volcano produces more CO2 than all the cars ever made have, but others have said that is not true, which is correct?”
I suspect that in this particular case, the one volcano loses to all the cars, but I haven’t done the sums.
http://www.skepticalscience.com/argument.php?p=4&t=236&&a=28
“Volcanoes emit around 0.3 billion tonnes of CO2 per year. This is about 1% of human CO2 emissions which is around 29 billion tonnes per year.”
This is an unreliable source, but in this particular case I have no reason to doubt it. Of course, it still has to be broken down for the actual question, but their figures suggest that the single volcano might lose the contest.
I do find it interesting that they go on to say “In fact, the rate of change of CO2 levels actually drops slightly after a volcanic eruption, possibly due to the cooling effect of aerosols.“. They do love those aerosols when there’s cooling. They may be right, but it seems rather obvious to me that when there’s a major eruption, the blocking of sunlight cools the oceans which then absorb more CO2. Is all the blocking done by aerosols? I don’t know, but mine seems to be the simpler explanation.
A couple of glasses of Brennevin (Black Death) and all will become clear in the following joke from an Icelandic friend:
The economy has died, been cremated and its ashes are being scattered all over Europe.
I do hope that all these references to Genesis, the Bible etc. are a joke, yes? Here in the UK we’re often told about the USA’s ‘problem’ concerning religion (like no Senator being atheist, or the film [movie] ‘Darwin’ being released everywhere across the globe, but not in the US). It doesn’t tend to figure in scientific debate over here, so are some commentators here on this forum having a little laugh, or are they serious?
Note to moderator: Please note that this post isn’t about religion per se, but about comments being made on the subject of water.
Here’s Eyjafjallajökull’s webcam.
http://eldgos.mila.is/eyjafjallajokull-fra-valahnjuk/
It’s quietened down a lot now.
Looks like plenty of ash from this volcano to me: http://www.nasa.gov/images/content/444588main_icelandvolcano-20100615.jpg
http://www.flickr.com/photos/gsfc/4530571303/
What does this mean for the Yellowstone super volcano.
Bad news if you’re a Discovery Channel documentary producer, looking to make a low budget feature.
Good news for the Heartland of America though.
I heard an interesting take on the disruption of the Icelandic volcano on BBC radio today. It said:
“Good news for the carbon budget with all of those grounded planes.”
Eh?
I wonder what they think comes out of volcanoes?
Plenty of ash spewing out of that Icelandic volcano from what I saw on the TV last night. I wouldn’t be too sure that the “steam” has actually come out of the volcano anyway – as there is a lot of cloud there is a lot of water vapour on the vicinity – could be the water vapour in the air is condensing around fine ash.
By the way, flights were stopped not due to a computer simulation but on the basis of test flights with small propellor aircraft that went up to collect ash samples. As a regular flier I’m not sure I want to put flying in ash to the test myself – those small particles of pumice probably don’t do a jet engine much good. They may find that opening up flights won’t result in a rush of people queuing to buy tickets!
Thanks for another excellent post Steven, got me thinking again!
I read somewhere that there is evidence of water being made in the upper atmosphere due to chemical processes. I suspect that weathering of rocks and other chemical processes also produce water.
Regarding the climatic effects of eruptions, the gases/ash produced seem to be heavily ionised and this would increase their effectiveness to act as nucleation centres for precipitation.
Good picture of the electrical effects here:-
http://davidthompson.typepad.com/.a/6a00d83451675669e20133ecc09b5f970b-800wi
So sorry Steve,but didn’t you know Iceland is too far north for volcanoes(Sanchez,CNN).???? What are you going to say when we figure out Antartica is the most active volcanic region in the world?/sarc off
I understood that volcanic activity has an effect on climate, not ‘tother way about. In today’s Guardian, a writer is pleading for funding to enable scientists to study the threat that climate change is to increased volcanic activity so that, eventually, those scientists may save the world..
I also understood that the same newspaper has a ‘Science Editor’ who has some scientific qualifications. Does he not proofread the mad stuff his staff hand in, or does the Guardian have a New Science agenda?
fhsiv (23:54:33) :
The viscosity of magma is largely dependent on the amount of volatiles, like water, mixed in. Icelandic basalt is similar in composition to Hawaiian basalt, but we don’t see much steam or ash coming out of Hawaiian volcanoes.
Matt (01:54:56) :
Places where the plume is dark is indicative of the presence of ash. Ash is much more dense than air, and would not rise upwards very far unless it was being lifted by hot gases, like steam.
The Mt St Helens eruption was interesting because you could see large amounts of ash falling back to earth out of the rising plume. And note in the Mayon image above, you can clearly see that the darker material is tending to move downwards while the lighter material (mostly steam) is moving upwards.
Alexander (04:05:48) :
I saw that Guardian article and practically choked. Some former scientist appears to have sold his soul.
Tenuc (02:49:06) :
A rising plume of very hot gas and ash generates a lot of friction, and thus charged particles and lightning.
Steven,
Science rarily digs deep enough for the imporatant questions and science is rare to be correct. Huge areas of our basic knowledge are missing with theories that put under pressure fall apart.
Mass under high enough heat can burn and turn into a gas and ash. Our core made of nickel? And taking 2 billion years to form? Did we not have gravity and electrical field them? Moon slows the planet? Gravity is created from mass?
NO!
All these areas deal with understanding the relationship of rotation to gases and mass. Science lumped both together but there properties are totally different. Just the basic understanding of rotation is an extremely complex area that shows how mass can be compressed and the interaction of energy.
Why after 4+ billion years, we still have quakes and volcanoes? When pressure is released, the energy should be gone but it builds up again over time, why?
Only concept we have of our interior is from reading of earthqukes to the density of the interior.
The only explanation that fits all areas is that our core is super compressed gases like the sun that can take high pressure and emmense heat. When rotating mass, the centrifugal force forces mass to the outside(in our case the mantle and crust). When the planet slows, the gases expand minutely, keeping pressure building under the crust.
In the universe, gases are the most abundant and everything rotates and is moving.
Thanks Steve good work.
I think big oil had something to do with this eruption…maybe they were doing that horizontal drilling and caused the eruption….they are hoping the ash will temporarily reverse the effects of AGW long enough so people will forget that CO2 is EVIL!!!! (sarc off)
Einar Kjartansson, a geophysicist at the Icelandic Meteorological Office explains what is happening :
http://www.reuters.com/article/idUSLDE63H0OV20100418?type=marketsNews
Look away if you come out in a rash when you hear anything related to the bible
and I agree, this is not the place for a religion discussion. Having said that…..
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Walter M. Clark (20:33:36) :
johnythelowery (19:29:37)
You aren’t going far enough back.
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Actually, I wasn’t going forward far enough. As what Peter really said was
‘….the earth was formed out of water and by water. By these same waters also the earth was deluged and destroyed!…..” 2Pe Ch3v6
As the ‘deluge’ referred to is Noah’s—which possits a flooding to the ‘top of highest mountain-(yes, i know)–it was quickly falsifiable by the volume of water needed let alone other problems. Not anymore. ‘……..The amount of water stored in rocks of the primary lithosphere is estimated at 25E21kg (Hutchinson G E, 1957), whereas the water in all oceans is 1.35E21kg, so it is quite possible that all this water emerged slowly after rocks were compressed and heated while the atmosphere had cooled already….’
What ever Peter was trying to say, with his mouth full, was some primary role of water in the formation of the earth which i feel is counter intuitive and appears to be true. But, that’s it. Sorry. Shouldn’t mention this. People are aware of Genesis but not Peter’s remark (we can discuss Bart Ehrman’s take else where…and Dawkins). Thx.
Ac
The early atmosphere could have contained all that water if it were much denser and hotter. Don’t you think It probably was when the surface of the earth was still molten.
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Maybe nitpicking, but let’s remember: clouds don’t consist of water vapour. It is water. Aerosol
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This is interesting (to me)…….a H2O molecule and a …..what is Aerosol?
(I can feel the Solar issue standing in the back ground)